Disc stacking arrangement

ABSTRACT

Centrifuge for purifying flowing fluid media, has a plurality of stacked concentric disc elements, each provided with a central fluid inlet hole. The disc elements have through openings and the disc elements are slipped thereonto at least three substantially axially extending, circumferentially spaced guide elements for guiding the disc elements circumferentially and radially. The disc elements are held together by end elements at the ends of the stack of discs. The guide elements are completely separate, combined guidance and tensile rods, which are disposed so as not to encroach on the central flow space in the disc stack. The through openings in the disc elements are made as notches, radially directed from the central fluid inlet hole in the disc elements, and the tensile rods are disposed to be inclined somewhat towards the rotational centre from the lower end element when mounting the disc elements.

TECHNICAL FIELD

The present invention relates to an arrangement in a centrifuge forpurifying flowing fluid media, said centrifuge comprising a plurality ofconcentrically stacked disc elements provided with at least a centrallydisposed fluid inlet hole, said disc elements having through openings bymeans of which the disc elements are slipped onto at least threeessentially axially standing, circumferentially spaced, guide elementsfor guiding the disc elements circumferentially and radially, and saiddisc elements being held together by end elements at the ends of thestack of discs, said guide elements being in the form of separatetensile rods, which are disposed to cooperate with the end elements insuch a manner that the end elements are displaceable relative to eachother when compressing the disc elements, means being arranged tolockingly engage the combined guiding and tensile rods to hold the discelements m a compressed state.

BACKGROUND OF THE INVENTION

In arrangements of this type for purifying a liquid from undesirableparticles there is sometimes used a fixed guiding and tensioning elementin the form of a central so-called wing cross to make possible bothradial and polar guidance and compression of a large number of stackedconical plates or disc elements (“insert plates”) with the aid ofpressure elements at either end of the stack of discs. The pressureelements can be upper and lower end plates which are coupled togethervia threads with the fixed guidance and tensioning element, or by ahousing surrounding and rotating together with the disc stack and havingupper and lower halves coupled together. By tightening the end plates tothe guidance and tensioning element or to the halves of the housing, thedisc elements are pressed together in the stack to make a stable unit.

In centrifuges for gas purification, it is, however, not advantageous towork with an outer rotating housing. Nor is the use of a central wingcross suitable. This limits the flow space for the gas medium flowinginto the centre of the disc stack. Furthermore, the mounting of the discelements on the fixed guide elements is problematic and requiresprecision and narrow dimensional tolerances.

U.S. Pat. No. 5,637,217 describes a centrifuge for separating particlesfrom a circulating liquid and has features of the type which aredisclosed in the preamble to claim 1. The through openings through thedisc elements in this centrifuge are, however, not made to simplify themounting of the disc element and the tensioning bars.

THE PURPOSE AND SOLUTION OF THE INVENTION

One purpose of the present invention is to achieve a centrifuge in whichthe disc elements can be easily assembled into a disc stack on the guideelements and be compressed by the end compression elements cooperatingwith the guide elements, while at the same time assuring that there willbe a large central flow space for the inflowing medium to be purified.

For this purpose the arrangement described by way of introduction ischaracterized according to the invention in that the through openings inthe disc elements for the tensile rods are in the form of notchesradially directed from the central fluid inlet hole in the discelements.

In order to additionally simplify assembly of the disc elements, thetension bars are disposed when the disc elements are slipped onto thesame to be able to be inclined somewhat inwards towards the rotationalcentre from one end element to facilitate stacking. After mounting ofthe last disc element, the bars are pressed outwardly for mounting ofthe upper end element.

In the event of a rotor breakdown, to prevent the more rigid endelements from striking and damaging a surrounding housing, these arepreferably made with an outer diameter which is less than the outerdiameter of the disc elements. The more deformable, thin disc elementswill strike the housing instead.

Additional features and advantages of the present invention will beevident from the following detailed description with reference to theaccompanying drawing.

SHORT DESCRIPTION OF THE DRAWING

FIG. 1 is a partially sectioned side view of a centrifuge arrangementaccording to the present invention;

FIG. 2 is a plan view of the arrangement in FIG. 1;

FIG. 3 is an exploded View in perspective of the arrangement in FIGS. 1and 2; and

FIG. 4 is an enlarged detail view of the area circled in FIG. 1, showingthe coupling together of an upper pressure element with a guiding andtensioning element in the arrangement according to FIGS. 1-3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In FIG. 1, 10 designates a rotor of a centrifuge for purifying a gasmedium. The rotor 10 has a bottom element 14 which is integrated with adrive shaft 12 and has a conical collar 16, which is connected via aradial web portion 18 and a hub 20, to a centrally placed drive shaft12. Onto the bottom element 14 there are stacked a plurality of spacerelements in the form of conical discs 22. The discs 22 are stacked withthe aid of four axially directed guide rods 24, which are mounted evenlydistributed peripherally. Each disc 22 has, for this purpose, fourcorresponding guide grooves or through openings 26, which preferablyextend radially into the discs 22 from an inner circumferential edge 28,which defines a central inlet hole 30 for the gas medium to be purified.The discs 22 are held spaced from each other a small distance in theaxial direction by means of suitable spacers, e.g. radial ridges 32,which are indicated in FIG. 4.

The guide rods 24, which can be made as a long tubular elements with aninner thread at their ends, are, at their lower ends shown in FIGS. 1and 3, fixed in the bottom element 14 by means of screws 34. At theupper ends of the guide rods 22, a pressure plate 36 is applied. Thepressure plate 36 has a conical collar portion 38 which abuts againstthe top of the upper disc 22 in the stack as well as a hub portion 40with four mounting holes 42 (FIG. 4) for the upper ends of the guiderods 24. Screws 44 engage the thread in the upper ends of the guide rods22 and press the conical collar portion 38 against the upper disc 22 inthe stack, to thereby hold the discs 22 stably together and press thembetween the bottom element 14 and the pressure plate 36 of the rotor 10.The rods 24 are in this case both guide elements for stacking the discs22, and pressure elements for pressing them together, at the same asthey encroach minimally on the central flow space for the gas medium tobe purified, flowing into the rotor.

In order to facilitate slipping the discs 22 onto the guide rods 24, theguide rods are preferably disposed during assembly to be inclinedsomewhat inwardly towards the rotational centre. This can be achieved bymaking the mounting holes for the guide rods 24 and the bottom element14 somewhat inwardly inclined or by bending the rods 24 somewhatinwardly by means of the first mounted disc element. When mounting thepressure plate 36 on top of the uppermost disc 22, the rods 24 can bepressed into their respective through openings 26 in the discs. Anyclearances or gaps between the rods 24 and the through openings 26(guide grooves) can be taken up by the rods being pressed outwardly bythe centrifugal forces during operation. Such an intentional gap canfurther facilitate the mounting of the discs 22.

It is suitable to make the pressure plate 36 and the bottom element 14with an outer diameter which is somewhat less than the outer diameter ofthe discs 22. In the event of breakdown of the rotor shaft 12, the moredeformable discs 22, preferably made of a plastics material, will comeinto contact with a surrounding housing, instead of the more rigidbottom element 14 or the pressure plate 36, coming into contact with thesurrounding housing, thus minimising damage to the centrifuge.

Many modifications of the device are conceivable within the scope of theinvention. For example, instead of screws 34, 44, nuts can be used whichengage externally threaded end portions of the guide rods 24. The numberof guide rods 24 should be at least three, but can be more than four.Furthermore, the end portion of the rotor, integrated with the driveshaft, can be a displaceable pressure plate for the stack of discs,while the opposite end element can be a fixed component with guide rodson which the discs are mounted.

1. Arrangement for a centrifuge for purifying flowing fluid media, saidcentrifuge comprising a plurality of concentrically stacked discelements (22) provided with at least a centrally disposed fluid inlethole (30), said disc elements (22) having through openings (26) by meansof which the disc elements (22) are slipped onto at least threeessentially axially standing, circumferentially spaced, guide elements(24) for guiding the disc elements circumferentially and radially, andsaid disc elements (22) being held together by end elements (14, 36) atthe ends of the stack of discs, said guide elements being in the form ofseparate tensile rods (24), which are disposed to cooperate with the endelements (14, 36) in such a manner that the end elements aredisplaceable relative to each other when compressing the disc elements(22), means (34, 44) being arranged to lockingly engage the combinedguidance and tensile rods (24) to hold the disc elements (22) in acompressed state, characterized in that the through openings (26) in thedisc elements (22) for the tensile rods (24) are in the form of notchesradially directed from the central fluid inlet hole (30) in the discelements (22).
 2. Arrangement according to claim 1, characterized inthat the tensile rods (24) are arranged upon slipping of the discelements (22) onto the same, to be inclineable somewhat inwards towardsthe rotational centre from one of the end elements (14) to facilitatemounting.
 3. Arrangement according to claim 1, characterized in that theend elements (14, 36) have an outer diameter which is less than theouter diameter of the disc elements (22).
 4. Arrangement according toclaim 2, characterized in that the end elements (14, 36) have an outerdiameter which is less than the outer diameter of the disc elements(22).